I can't purchase any songs or apps it show decline message
When I want to make payment I can't do it but it shows decline transaction
iPhone 5, iOS 9.2
What are you trying to use as your payment method, credit card, debit card ... ? If it's a debit card then not all seem to still be accepted, and might not be accepted at all in some countries.
For a card to have a chance of being accepted it needs to be registered to the same name and address (including format and spacing etc) that you have on your iTunes account, and have been issued by a bank in the country where you are (and therefore the country which is on your iTunes account). If it is then you could check with the card issuer to see if it's them that are declining it. If they aren't then have you got a different card to try ?